This invention relates generally to portable air blowers often used when drying carpets. More particularly, this invention relates to an air blower having motor driven fan means internally supported by an improved mounting arrangement that absorbs impact-created shock forces and incidental vibration.
Portable air blowers are well known and typically include an electric motor and a blower wheel or fan, which are contained within a housing having an air intake vent and an air exhaust vent. Exemplary of prior devices is the squirrel cage fan air blower, which has drawbacks in common with other prior air blowers. More particularly the squirrel cage fan, as originally developed many years ago, was designed for stationary use only. The squirrel cage fan was not designed for use in portable equipment and, consequently, it was not constructed to withstand the abuse that portable equipment is often subjected to. This is apparent from the structure of a squirrel cage fan, in which the fan is supported by a weak, centrally located, single mounting hub that is insufficient to withstand multi-directional shock forces encountered when portable equipment is dropped or roughly handled while in a running mode. Historically, the life expectancy of squirrel cage fan air blowers has been relatively short.
The problems associated with prior air blowers have arisen due to the very nature of such blowers. In particular, in order to move a high volume of air, the blowers are designed to rotate a large fan or blower wheel as fast as possible within the blower housing. This requires that the motor and the blower wheel be precisely aligned within the housing so as not to create unwanted and possibly destructive vibration.
Portable air blowers are often subjected to rough handling during transportation and in use. Prior designs, characterized by an internal mounting arrangement which rigidly supports the blower means within the housing, attempted to protect the internal air blower components by providing stiffly resilient housings capable of absorbing some impact-created forces. It has been found that, in spite of all previous precautions, the internal components of prior portable air blowers invariably eventually become tweaked or misaligned as they are repeatedly subjected to jarring, impact-created shock forces. Such misalignment occurs partly due to the rigid nature of the mounting arrangement of the motor and blower wheel within the housing, which often precludes the absorption or damping of these impact-created shock forces by flexion.
The result of a misorientation of the motor and/or blower wheel within the housing is the creation of undesirable vibration within the air blower. Vibration within a portable air dryer is very undesirable because it can cause the blower to bounce or walk across a hard surface. As the vibration becomes progressively worse, mechanical parts of the blower begin to wear out prematurely, which ultimately renders the air blower unusable.
There exists, therefore, a significant need for a portable air blower having means for mounting the motor and the blower wheel within the housing in a manner permitting limited and temporary flexion of the motor and the blower wheel with respect to the housing when the air blower is subjected to impact-created shock forces. Additionally, a portable air blower having such a mounting arrangement is needed which returns the motor and the blower wheel to a preferred position within the housing immediately following and in the absence of shock forces. Such an improved mounting arrangement should be compatible with standard portable air blower design and result in no degradation in the capability of such air blowers. Further, a novel mounting arrangement is needed which is relatively inexpensive, durable and reliable. An arrangement utilizing similar parts for mounting each end of the blower means, or motor and blower wheel assembly, within the housing would be preferred. The present invention fulfills these needs and provides further related advantages.